Apex domains cannot have CNAME records.
Question and response
Question
dig newtonsoftware.com. NS
Answer
newtonsoftware.com. 5 NS ns-876.awsdns-45.net.
newtonsoftware.com. 5 NS ns-1767.awsdns-28.co.uk.
newtonsoftware.com. 5 NS ns-43.awsdns-05.com.
newtonsoftware.com. 5 NS ns-1422.awsdns-49.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0